1 files changed, 98 insertions, 23 deletions

diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 782eecb57e43..3b0e3bdaabfc 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -90,11 +90,91 @@ ext4_unaligned_aio(struct inode *inode, const struct iovec *iov,
 }
 
 static ssize_t
+ext4_file_dio_write(struct kiocb *iocb, const struct iovec *iov,
+                    unsigned long nr_segs, loff_t pos)
+{
+        struct file *file = iocb->ki_filp;
+        struct inode *inode = file->f_mapping->host;
+        struct blk_plug plug;
+        int unaligned_aio = 0;
+        ssize_t ret;
+        int overwrite = 0;
+        size_t length = iov_length(iov, nr_segs);
+
+        if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) &&
+            !is_sync_kiocb(iocb))
+                unaligned_aio = ext4_unaligned_aio(inode, iov, nr_segs, pos);
+
+        /* Unaligned direct AIO must be serialized; see comment above */
+        if (unaligned_aio) {
+                static unsigned long unaligned_warn_time;
+
+                /* Warn about this once per day */
+                if (printk_timed_ratelimit(&unaligned_warn_time, 60*60*24*HZ))
+                        ext4_msg(inode->i_sb, KERN_WARNING,
+                                 "Unaligned AIO/DIO on inode %ld by %s; "
+                                 "performance will be poor.",
+                                 inode->i_ino, current->comm);
+                mutex_lock(ext4_aio_mutex(inode));
+                ext4_aiodio_wait(inode);
+        }
+
+        BUG_ON(iocb->ki_pos != pos);
+
+        mutex_lock(&inode->i_mutex);
+        blk_start_plug(&plug);
+
+        iocb->private = &overwrite;
+
+        /* check whether we do a DIO overwrite or not */
+        if (ext4_should_dioread_nolock(inode) && !unaligned_aio &&
+            !file->f_mapping->nrpages && pos + length <= i_size_read(inode)) {
+                struct ext4_map_blocks map;
+                unsigned int blkbits = inode->i_blkbits;
+                int err, len;
+
+                map.m_lblk = pos >> blkbits;
+                map.m_len = (EXT4_BLOCK_ALIGN(pos + length, blkbits) >> blkbits)
+                        - map.m_lblk;
+                len = map.m_len;
+
+                err = ext4_map_blocks(NULL, inode, &map, 0);
+                /*
+                 * 'err==len' means that all of blocks has been preallocated no
+                 * matter they are initialized or not.  For excluding
+                 * uninitialized extents, we need to check m_flags.  There are
+                 * two conditions that indicate for initialized extents.
+                 * 1) If we hit extent cache, EXT4_MAP_MAPPED flag is returned;
+                 * 2) If we do a real lookup, non-flags are returned.
+                 * So we should check these two conditions.
+                 */
+                if (err == len && (map.m_flags & EXT4_MAP_MAPPED))
+                        overwrite = 1;
+        }
+
+        ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos);
+        mutex_unlock(&inode->i_mutex);
+
+        if (ret > 0 || ret == -EIOCBQUEUED) {
+                ssize_t err;
+
+                err = generic_write_sync(file, pos, ret);
+                if (err < 0 && ret > 0)
+                        ret = err;
+        }
+        blk_finish_plug(&plug);
+
+        if (unaligned_aio)
+                mutex_unlock(ext4_aio_mutex(inode));
+
+        return ret;
+}
+
+static ssize_t
 ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
                 unsigned long nr_segs, loff_t pos)
 {
         struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode;
-        int unaligned_aio = 0;
         ssize_t ret;
 
         /*
@@ -114,29 +194,12 @@ ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
                         nr_segs = iov_shorten((struct iovec *)iov, nr_segs,
                                               sbi->s_bitmap_maxbytes - pos);
                 }
-        } else if (unlikely((iocb->ki_filp->f_flags & O_DIRECT) &&
-                   !is_sync_kiocb(iocb))) {
-                unaligned_aio = ext4_unaligned_aio(inode, iov, nr_segs, pos);
         }
 
-        /* Unaligned direct AIO must be serialized; see comment above */
-        if (unaligned_aio) {
-                static unsigned long unaligned_warn_time;
-
-                /* Warn about this once per day */
-                if (printk_timed_ratelimit(&unaligned_warn_time, 60*60*24*HZ))
-                        ext4_msg(inode->i_sb, KERN_WARNING,
-                                 "Unaligned AIO/DIO on inode %ld by %s; "
-                                 "performance will be poor.",
-                                 inode->i_ino, current->comm);
-                mutex_lock(ext4_aio_mutex(inode));
-                ext4_aiodio_wait(inode);
-        }
-
-        ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
-
-        if (unaligned_aio)
-                mutex_unlock(ext4_aio_mutex(inode));
+        if (unlikely(iocb->ki_filp->f_flags & O_DIRECT))
+                ret = ext4_file_dio_write(iocb, iov, nr_segs, pos);
+        else
+                ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
 
         return ret;
 }
@@ -181,9 +244,21 @@ static int ext4_file_open(struct inode * inode, struct file * filp)
                 path.dentry = mnt->mnt_root;
                 cp = d_path(&path, buf, sizeof(buf));
                 if (!IS_ERR(cp)) {
+                        handle_t *handle;
+                        int err;
+
+                        handle = ext4_journal_start_sb(sb, 1);
+                        if (IS_ERR(handle))
+                                return PTR_ERR(handle);
+                        err = ext4_journal_get_write_access(handle, sbi->s_sbh);
+                        if (err) {
+                                ext4_journal_stop(handle);
+                                return err;
+                        }
                         strlcpy(sbi->s_es->s_last_mounted, cp,
                                 sizeof(sbi->s_es->s_last_mounted));
-                        ext4_mark_super_dirty(sb);
+                        ext4_handle_dirty_super(handle, sb);
+                        ext4_journal_stop(handle);
                 }
         }
         /*